Manufacturing method of synthetic resin hollow body

ABSTRACT

A manufacturing method of a synthetic resin hollow body in which a molten resin is injected for an over-molding outside a hollow molding body made of a resin provided with a hollow body and at least an opening portion to form a resin sheathing body in an integrating manner with the hollow molding body. The method includes the step of injecting the molten resin for an over-molding under the state in which the hollow molding body is partially or wholly filled with a fluid substance. The manufacturing method of a synthetic resin hollow body is capable of suppressing resin cost and operation cost and can improve decorating property.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.12/373,878 filed on Jan. 14, 2009, which is a U.S. national stageapplication of International Application No. PCT/JP2007/064536 filed onJul. 18, 2007 and which claims priority to Japanese Application Nos.2006-197498 filed on Jul. 19, 2006 and 2007-137210 filed on May 23,2007, the entire contents of all of which are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a manufacturing method of a syntheticresin hollow body (A) for holding a liquid material having a flowproperty such as a cosmetic solution, a chemical, and drinking water.

BACKGROUND ART

As a container for holding a liquid material such as a cosmeticsolution, a chemical, and drinking water, a container with a cap havingan excellent corrosion resistance and a satisfactory airtight propertyhas been widely used. The container is generally made of a glass. Insome cases, a metal container can also be used to obtain similareffects.

The glass container has a dignity sense and a high quality sense,thereby being suitably used for a container of a cosmetic solution inparticular. However, in some cases, the glass container may be easilydamaged by a shock during a carrying operation or by a drop in use.

On the other hand, the metal container has an excellent shock resistancein particular. However, a weight and a raw material cost thereof areincreased, and a processing thereof has a lot of trouble.

In many cases, the glass container and metal container are in a simpleshape, thereby being lacking in a decorating property.

As shown in FIG. 10, Patent document 1 proposes a composite container104 in which a resin is over-molded on a container 100 made of a glassor a metal to form a resin sheathing body 102 outside the container 100in order to add a design property.

On the other hand, in the case in which the container is made of asynthetic resin, the container is manufactured by a method such as ablow molding method and a method of forming two divided molding bodiesin advance and of welding the two bodies using a vibration weldingmethod, thereby reducing a manufacturing cost and enabling a massproduction.

However, the blow molding method just enables a formation of only athin-walled container. Consequently, a shape of the container isrestricted to a certain degree, thereby being lacking in a decoratingproperty in some cases.

Moreover, the method of welding the two divided molding bodies using avibration welding method enables a manufacture of a container in a freeshape as compared with the blow molding method. However, in the case inwhich a liquid material to be held in the container is a chemical or thelike, a material of the container is restricted to a costly resin havingan excellent chemical resistance, thereby increasing a resin costdisadvantageously.

As a method to solve the above problems, Patent document 2 discloses asynthetic resin hollow body 206 as shown in FIG. 11. To form thesynthetic resin hollow body 206, an inner shell 200 is formed at firstby combining divided molding bodies or by a blow molding method. Amolten resin made of a material equivalent to or other than that of theinner shell 200 is then injected outside the inner shell to form anover-molded portion 202, thereby integrating the over-molded portion 202with the inner shell 200.

Such a synthetic resin hollow body 206 has a two-layer structure,thereby further improving a decorating property.

Moreover, a resin having an excellent chemical resistance can be usedfor only the inner shell 200, and a comparatively low cost resin can beused outside the inner shell, thereby reducing a total resin cost forthe synthetic resin hollow body 206.

-   Patent document 1: Japanese Unexamined Patent Application    Publication No. 2004-527424-   Patent document 2: Japanese Patent Application Laid-Open Publication    No. 06-23758

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, for such a composite container 104 disclosed in Patent document1, a material of the core container 100 is a glass or a metal, therebyrestricting processability to a certain degree. Consequently, a degreeof freedom for a design is insufficient and not satisfactory.

The glass container 100 in such a composite container 104 is covered bythe resin sheathing body 102. However, since the core container 100 ismade of a glass, a damage caused by a drop cannot be prevented in manycases.

The composite container 104 is made of a combination of differentmaterials composed of a glass and a resin. Consequently, the glass andthe resin must be separated in a disposal, thereby involving adisadvantage in relation to a recycle property.

For the synthetic resin hollow body 206 disclosed in Patent document 2,a thickening material such as a super absorbent resin is injected intothe inner shell 200 in advance, and is frozen and hardened to be a corematerial 204 before set in a metal mold 208, in such a manner that theinner shell 200 is prevented from being deformed or damaged by a resinpressure of a molten resin in the case in which a molten resin isinjected outside the inner shell 200 in an integrating manner. After anintegrating molding with the inner shell 200, the core material 204 inthe inner shell 200 must be molten and removed. Consequently, there aremany complicated operation processes.

Before the synthetic resin hollow body 206 is used, a thickeningmaterial that has adhered inside the inner shell 200 must be cleaned,thereby deteriorating productivity.

Moreover, although this method can suppress a resin cost, an operationcost is increased disadvantageously.

The present invention was made in consideration of such conditions, andan object of the present invention is to provide a manufacturing methodof a synthetic resin hollow body capable of suppressing a product costand an operation cost.

Means for Solving the Problems

The present invention was made in order to solve the above problems ofthe conventional art. A manufacturing method of a synthetic resin hollowbody (A) in which a molten resin is injected for an over-molding outsidea hollow molding body (a) made of a resin provided with a hollow bodyand at least an opening portion to form a resin sheathing body in anintegrating manner with the hollow molding body (a) in accordance withthe present invention is characterized by comprising the step ofinjecting the molten resin for an over-molding under the state in whichthe hollow molding body (a) is partially or wholly filled with a fluidsubstance.

By such a configuration, the hollow molding body (a) can be preventedfrom being deformed by a resin pressure in molding, therebymanufacturing the synthetic resin hollow body (A) in which an externalsurface of the hollow molding body (a) is reliably covered by the resinsheathing body in an integrating manner.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that the resinsheathing body is preferably welded to an external surface of the hollowmolding body (a).

As described above, the resin sheathing body is welded to an externalsurface of the hollow molding body (a), thereby preventing the hollowmolding body (a) from wobbling or rotating inside the resin sheathingbody.

Moreover, the boundary line between the both members is hardly visible,thereby obtaining the synthetic resin hollow body (A) having an improvedaesthetic appreciation.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized by comprising thesteps of filling partially or wholly the hollow molding body (a) with aliquid as a fluid substance; attaching a cap member to the openingportion; setting the hollow molding body (a) holding the liquid insideto a metal mold; and injecting a molten resin for an over-molding,wherein the liquid is one of water, an aqueous solution, a cosmeticsolution, a chemical, and an organic solvent.

By attaching the cap member to the opening portion as described above, afluid substance (a liquid in particular) can be prevented fromscattering externally out of the opening portion, and the hollow moldingbody (a) can be safely set to a metal mold even in the case in which thefluid substance such as a chemical accompanied by a danger in a handlingis used.

As described above, since the fluid substance is a liquid, the hollowmolding body (a) can be prevented from being deformed by a resinpressure in molding, thereby manufacturing the synthetic resin hollowbody (A) in which an external surface of the hollow molding body (a) isreliably covered by the resin sheathing body in an integrating manner.

Moreover, in the case in which the fluid substance is water, after thesynthetic resin hollow body (A) is manufactured, only removing water anddrying enable a desired cosmetic solution or the like to be newly held,thereby facilitating the manufacturing.

Furthermore, in the case in which the hollow molding body (a) is filledwith a cosmetic solution or the like to be held in advance in molding,the synthetic resin hollow body (A) can be a product for a marketimmediately after the manufacturing, thereby further facilitating themanufacturing process.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that a boilingpoint of the liquid is preferably at least 50° C.

By setting a boiling point of the liquid as described above, the liquidcan be prevented from being vaporized in a metal mold in molding,thereby manufacturing the synthetic resin hollow body (A) in which anexternal surface of the hollow molding body (a) is safely and reliablycovered by the resin sheathing body in an integrating manner.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that the fluidsubstance is a gas preferably.

As described above, since the fluid substance to be filled in the hollowmolding body (a) is a gas, the synthetic resin hollow body (A) can be aproduct for a market immediately after the over-molding, thereby furtherimproving productivity as compared with the case in which the fluidsubstance is a liquid.

The manufacturing method of a synthetic rosin hollow body (A) inaccordance with the present invention is characterized in that the gasis preferably one of air, nitrogen, oxygen, an inert gas, and a carbondioxide gas.

In the case in which the gas is one of the above gases, the hollowmolding body (a) can be reliably prevented from being deformed by aninjection pressure in an injection.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that the gasis blown into the hollow molding body (a) in an injection of the moltenresin, and a gas pressure in the hollow molding body (a) in a period ofa cooling of the molten resin is preferably held to be lower than theblowing pressure of the gas blown in the injection of the molten resinin the case in which the molten resin is injected into the metal mold.

By adjusting a gas pressure in the hollow molding body (a) in aninjection of the molten resin and in a cooling of the molten resin asdescribed above, the hollow molding body (a) can be prevented from beingdeformed by an injection pressure in an injection, and a distortion canbe reliably prevented from being generated between the hollow moldingbody (a) and the resin sheathing body in a cooling.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that apressure of the gas to be blown into the hollow molding body (a) ispreferably in the range of 0.04 to 1.0 MPa in a period from the start tothe end of the injection of the molten resin.

By adjusting a gas pressure in the range as described above, the hollowmolding body (a) can be effectively prevented from being deformed by aresin pressure.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that apressure of the gas in the hollow molding body (a) is preferably in therange of 0.02 to 0.5 MPa in a period of the cooling of the molten resin.

By adjusting a gas pressure in the range as described above, adistortion can be reliably prevented from being generated between thehollow molding body (a) and the resin sheathing body in cooling theresin.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that a moldingtemperature is in the range of 100° C. to 300° C. and an injectionpressure is in the range of 20 to 150 kg/cm² preferably in the case inwhich the molten resin is injected into the metal mold.

By setting the conditions for the metal mold in the range as describedabove, the fluid substance can be prevented from being vaporized in ametal mold in molding, thereby manufacturing the synthetic resin hollowbody (A) in which an external surface of the hollow molding body (a) issafely and reliably covered by the resin sheathing body in anintegrating manner.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that themolten resin to be injected into the metal mold is preferably an ionomerresin.

By using such a resin for a molding as described above, the hollowmolding body (a) is clearly visible via the resin sheathing body. Inaddition, the resin sheathing body has an extremely high transparency,thereby greatly improving a high quality sense, an aestheticappreciation, and an appearance property.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that thehollow molding body (a) is preferably formed by a blow molding method ora method of welding two divided molding bodies using a vibration weldingmethod.

By forming the hollow molding body (a) by such a method as describedabove, a mass production is possible and a manufacturing cost can bereduced, thereby also manufacturing the synthetic resin hollow body (A)in which an external surface of the hollow molding body (a) is coveredby the resin sheathing body in an integrating manner at a low cost.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that thehollow molding body (a) is a thin-walled molding body preferably.

As described above, since the hollow molding body (a) is a thin-walledmolding body, in the case in which the hollow molding body (a) isintegrated with the resin sheathing body, the boundary line between theboth members is hardly visible, thereby obtaining the synthetic resinhollow body (A) having an improved aesthetic appreciation.

Moreover, in the case in which a thin-walled molding body is formed by ablow molding method, productivity can be improved, and an amount of aresin to be used can be suppressed.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that athickness of the resin sheathing body is at least 1 mm preferably.

As described above, since a thickness of the resin sheathing body is atleast 1 mm, a dignity sense of a glass can be obtained, and the resinsheathing body can be formed in many kinds of shapes, thereby obtainingthe synthetic resin hollow body (A) having an improved aestheticappreciation.

The manufacturing method of a synthetic resin hollow body (A) inaccordance with the present invention is characterized in that thehollow molding body (a) is a hollow molding container preferably.

As described above, since the hollow molding body (a) is a hollowmolding container, a liquid material such as a cosmetic solution, achemical, and drinking water does not leak and can be held reliably.

Effect of the Invention

The present invention can provide a manufacturing method of a syntheticresin hollow body (A) capable of suppressing a product cost and anoperation cost by making a core hollow molding body (a) of a resin andby making a resin sheathing body of a highly transparent syntheticresin.

Moreover, an injection is carried out under the state in which a hollowmolding body (a) is partially or wholly filled with a fluid substance.Consequently, even in the case in which the hollow molding body (a) ismade of a resin, the hollow molding body (a) can be prevented from beingdeformed by an injection pressure, thereby obtaining the synthetic resinhollow body (A) in which the hollow molding body (a) is reliably coveredby the resin sheathing body.

The present invention can also provide a manufacturing method of asynthetic resin hollow body (A) that has a satisfactory decoratingproperty by making a core hollow molding body (a) of a resin and bymaking a resin sheathing body of a highly transparent synthetic resin.

Moreover, the present invention can provide a manufacturing method of asynthetic resin hollow body (A) that is hardly damaged even in the casein which the synthetic resin hollow body is dropped, by making a corehollow molding body (a) of a resin and by making a resin sheathing bodyof a highly transparent synthetic resin.

Furthermore, the present invention can provide a manufacturing method ofa synthetic resin hollow body (A) that is not required to be separatedin a disposal, thereby having a satisfactory recycle property, by makinga core hollow molding body (a) of a resin and by making a resinsheathing body of a highly transparent synthetic resin.

In the case in which a core hollow molding body (a) is made of a thinglass and has a thin-walled flat bottom, a crack may easily occur duringan over-molding of a resin sheathing body. However, the presentinvention adopts a hollow molding body (a) made of a resin, therebyfacilitating an over-molding.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a synthetic resin hollow body (A)in accordance with an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a synthetic resin hollow body(A) in accordance with an embodiment of the present invention.

FIG. 3 is a perspective view showing a synthetic resin hollow body (A)in accordance with another embodiment of the present invention.

FIG. 4 is a perspective view showing a synthetic resin hollow body (A)in accordance with another embodiment of the present invention.

FIG. 5 shows a hollow molding body (a) in accordance with anotherembodiment of the present invention. FIG. 5( a) shows a hollow moldingbody (a) with a cap opened, and FIG. 5( b) shows the hollow molding bodyof FIG. 5( a) that holds a liquid as a fluid substance and that isclosed by a cap member.

FIG. 6 illustrates a manufacturing method of a synthetic resin hollowbody (A) in accordance with an embodiment of the present invention. FIG.6( a) shows a state in which a hollow molding body (a) is set in a metalmold, FIG. 6( b) shows a state in which the metal mold is closed, andFIG. 6( c) shows a state in which a resin sheathing body is filled within such a manner that an external surface of the hollow molding body (a)is covered in an integrating manner with the resin sheathing body.

FIG. 7 illustrates a manufacturing method of a synthetic resin hollowbody (A) in accordance with an embodiment of the present invention. FIG.7( a) shows a state in which the metal mold is opened, and FIG. 7( b)shows a state in which the synthetic resin hollow body (A) is detachedfrom the metal mold.

FIG. 8 illustrates a manufacturing method of a synthetic resin hollowbody (A) in accordance with another embodiment of the present invention.FIG. 8( a) shows a state in which a hollow molding body (a) is set in ametal mold, FIG. 8( b) shows a state in which the metal mold is closed,and FIG. 8( c) shows a state in which a resin sheathing body is filledwith in such a manner that an external surface of the hollow moldingbody (a) is covered in an integrating manner with the resin sheathingbody.

FIG. 9 illustrates a manufacturing method of a synthetic resin hollowbody (A) in accordance with another embodiment of the present invention.FIG. 9( a) shows a state in which the metal mold is opened, and FIG. 9(b) shows a state in which the synthetic resin hollow body (A) isdetached from the metal mold.

FIG. 10 is a perspective view showing a conventional compositecontainer.

FIG. 11 is a process drawing illustrating a conventional manufacturingmethod of a synthetic resin hollow body (A).

EXPLANATIONS OF LETTERS OR NUMERALS

-   A: synthetic resin hollow body-   a: hollow molding body-   14: opening portion-   16: resin sheathing body-   18: cap member-   20: convex and concave portion-   22: liquid material-   24: metal mold-   26: metal mold-   28: resin inflow port-   30: liquid-   32: gas-   100: container-   102: resin sheathing body-   104: composite container-   200: inner shell-   202: over-molded portion-   204: core material-   206: synthetic resin hollow body-   208: metal mold

BEST MODE OF CARRYING OUT THE INVENTION

An embodiment (example) of the present invention will be described belowin detail with reference to the drawings.

FIG. 1 is a view showing a synthetic resin hollow body (A) in accordancewith an embodiment of the present invention. FIG. 2 is a cross-sectionalview showing the synthetic resin hollow body (A) of FIG. 1. FIGS. 3 and4 are views showing other embodiments of a synthetic resin hollow body(A). FIGS. 5 to 7 illustrate an embodiment of a method for manufacturinga synthetic resin hollow body (A).

<Synthetic Resin Hollow Body (A)>

A synthetic resin hollow body (A) in accordance with the presentinvention is for holding a liquid material having a flow property suchas a cosmetic solution, a chemical, and drinking water.

As shown in FIG. 1, the synthetic resin hollow body (A) is composed of ahollow molding body (inner bottle) (a) provided with an opening portion14 that is an inlet or an outlet for a liquid material 22 and a resinsheathing body 16 formed in such a manner that an external surface ofthe hollow molding body (a) is covered in an integrating manner with theresin sheathing body. That is, the resin sheathing body is over-moldedaround an external surface of the hollow molding body (a) in the presentinvention.

A cap member 18 is attached to the opening portion 14 of the hollowmolding body (a) to prevent the liquid material 22 from scatteringexternally out of the opening portion 14. In this embodiment, theopening portion 14 and the cap member 18 are screwed to each other.However, the present invention is not restricted to such aconfiguration. For instance, the cap member 18 can also be fitted intothe opening portion 14 in an inserting manner. After all, anyconfiguration that can prevent the liquid material 22 from scatteringexternally out of the opening portion 14 of the hollow molding body (a)can also be adopted.

Moreover, the liquid material 22 that is held in the synthetic resinhollow body (A) can be, for instance, water, an aqueous solution, or amixed solution of an oil component and an aqueous component such as acosmetic solution, a chemical, and an organic solvent. In the presentinvention, the liquid material includes a pasty material.

As shown in FIG. 2, for such a synthetic resin hollow body (A), theresin sheathing body 16 is formed to cover the entire of the hollowmolding body (a) from the bottom end of the opening portion 14.

In this embodiment, the resin sheathing body 16 is formed in a sphericalshape to a shape of the hollow molding body (a). In addition, the resinsheathing body 16 can also be decorated as shown in FIG. 3. After all,any shape can be adopted for the resin sheathing body 16.

A character or a graphic can be printed on an external surface of thehollow molding body (a) before forming the resin sheathing body 16. Inthis case, the printed section of the hollow molding body (a) isprotected by the resin sheathing body 16 at all times. Consequently, theprinted section can be maintained to be clean as long as possible.

As shown in FIG. 4, a decorative convex and concave portion 20 can beformed on an external surface of the resin sheathing body 16. By such aconfiguration, the synthetic resin hollow body (A) can have an increaseddesign variation, an aesthetic appreciation, and a high quality sense.

For such a synthetic resin hollow body (A), it is preferable to use ahighly transparent synthetic resin as a material of the resin sheathingbody 16. It is more preferable to use a synthetic resin having a totalray transmittance (conforming to JIS K7105, and measured with a sheethaving a thickness of 1 mm) in the range of 80% to 100%, more preferablyin the range of 85% to 100%.

As a material of a highly transparent synthetic resin that satisfies theabove range of a transmittance, an ionomer resin, an acrylic resin, apolyester resin, and styrene resins (such as a styrene acrylonitrilecopolymer resin and a styrene methylmethacrylate copolymer resin) can beused. Preferably, an ionomer resin and a polyester resin and ionomerresin can be used. More preferably, an ionomer resin can be used.

As an ionomer resin, a carboxyl group of an ethylene unsaturatedcarboxylic acid copolymer containing unsaturated carboxylic acid of 1 to40 weight % can be used for instance. At least part (generally more than0 mol % and up to 100 mol %, preferably up to 90 mol %) of the carboxylgroup is neutralized by metal ions.

An ethylene unsaturated carboxylic acid copolymer that is a base polymerof an ionomer resin can be obtained by copolymerizing ethylene, andunsaturated carboxylic acid, and optionally any other polar monomers. Asunsaturated carboxylic acid, acrylic acid, methacrylic acid, fumaricacid, maleic acid, anhydrous maleic acid, monomethyl maleate, andmonoethyl maleate can be mentioned. In particular, methacrylic acid ispreferable.

As a polar monomer that optionally can be a copolymer component, vinylester such as vinyl acetate and vinyl propionate, unsaturated carboxylicacid ester such as methyl acrylate, ethyl acrylate, isopropyl acrylate,n-butyl acrylate, isobutyl acrylate, n-hexyl acrylate, iso-octylacrylate, methyl methacrylate, dimethyl maleate, and diethyl maleate,and carbon monoxide can be mentioned. In particular, unsaturatedcarboxylic acid ester is a suitable copolymer component.

The metal ion is a metal ion having a valence of monovalence, bivalence,or trivalence, in particular, a metal ion having a valence ofmonovalence, bivalence, or trivalence of the groups IA, IIA, IIIA, IVA,and VIII in the element periodic law. More specifically, there can bementioned Na⁺, K⁺, Li⁺, Cs⁺, Ag⁺, Hg⁺, Cu⁺, Be⁺⁺, Mg⁺⁺, Ca⁺⁺, Sr⁺⁺,Ba⁺⁺, Cu⁺⁺, Cd⁺⁺, Hg⁺⁺, Sn⁺⁺, Pb⁺⁺, Fe⁺⁺, Co⁺⁺, Ni⁺⁺, Zn⁺⁺, Al⁺⁺⁺,Sc⁺⁺⁺, Fe⁺⁺⁺, and Y⁺⁺⁺.

The above materials are excellent in a transparency, a shock resistance,and a mar-proof property. In addition, a thick-walled molding ispossible and a dignity sense of a glass can be obtained. Consequently,these materials are suitable for a material of the resin sheathing body16. In the present invention, it is preferable that a thickness of theresin sheathing body 16 is at least 1 mm.

Any resin material can be used for the hollow molding body (a) and thecap member 18. For instance, a polyolefin resin, polyolefin resin (suchas polyethylene, polypropylene), polyester (such as PET (polyethyleneterephthalate), PETG, PEGT, PCT (polycyclohexane dimethyl naphthalate),PCTA, PEN (polyethylene naphthalate)), acrylic resin, styrene resin(such as a styrene acrylonitrile copolymer resin, styrene methylmethacrylate copolymer resin), cycloolefin polymer, polycarbonate,polyamide, ionomer resin, and PAN (polyacrylonitride) can be used. Inthe case in which a material the same as that of the resin sheathingbody 16 is used, a synergistic effect with the resin sheathing body 16can be obtained, thereby improving a high quality sense, an appearanceproperty, and an aesthetic appreciation.

As described later, the hollow molding body (a) is set in a metal mold,and a molten resin is flown into the metal mold and on an externalsurface of the hollow molding body (a) to form the resin sheathing body16. Consequently, it is preferable that the hollow molding body (a) ismade of polyester or polyamide that has a comparatively high meltingtemperature in the case in which a highly transparent synthetic resin isused.

In the case in which the liquid material 22 that is held in the hollowmolding body (a) is a chemical, it is preferable to use polyethylene orpolypropylene that has a comparatively excellent chemical resistance inhighly transparent synthetic resins.

Similarly to the above hollow molding body (a), for the cap member 18,it is preferable to use polyethylene or an ionomer resin that has acomparatively excellent chemical resistance in highly transparentsynthetic resins since the cap member 18 may partially come into contactwith the chemical.

Such a highly transparent synthetic resin may be colored or may have nocolor. Moreover, the hollow molding body (a), the resin sheathing body16, and the cap member 18 can have different colors from each other. Asa matter of course, in the case in which the hollow molding body (a) isa hollow molding body formed by a method of welding two molding bodiesusing a vibration welding method, the two molding bodies havingdifferent colors can be welded to form the hollow molding body (a).

In the case in which a blue highly transparent synthetic resin in whichHeliogen Blue K6911D (manufactured by BASF Company) is contained inionomer is used for molding, the material can be colored to be blue.

Even in the case in which a character or a graphic is generated on asurface of the hollow molding body (a), the character or the graphicthat has been generated on the hollow molding body (a) is visiblereliably from the outside of the resin sheathing body 16 by using such ahighly transparent synthetic resin. Consequently, a high quality sense,an aesthetic appreciation, and an appearance property can be improvedfor the synthetic resin hollow body (A).

Moreover, in the case in which a light reflecting powder (not shown) isdispersed in the highly transparent synthetic resin, a light isreflected from the light reflecting powder and glitters, thereby furtherimproving a high quality sense.

As such a light reflecting powder, it is preferable to use a lightreflecting powder in which a metal or metal oxide is coated on a surfaceof mica that is a core of the light reflecting powder.

<Manufacturing Method of the Synthetic Resin Hollow Body (A)>

Subsequently, the manufacturing method of the synthetic resin hollowbody (A) in accordance with the present invention will be describedbelow.

As shown in FIG. 5( a), a hollow molding body (a) is prepared at first.The hollow molding body (a) is previously manufactured by a blow moldingmethod or by a method of forming two divided molding bodies in advanceand welding the two bodies using a vibration welding method. Themanufacturing method is not restricted in particular. In the case inwhich a blow molding is carried out, the hollow molding body (a) can bea thin-walled molding body, and a thickness of the wall is preferably inthe range of 0.1 to 10 mm, more preferably in the range of 0.2 to 8 mm.

As shown in FIG. 5( b), liquid 30 is then flown as a fluid substanceinto the hollow molding body (a) via an opening portion 14, and a capmember 18 is attached to the opening portion 14. The liquid 30 to befilled with should be at least 50% of the total amount that can be flowninto the hollow molding body (a), preferably at least 70%, in such amanner that the hollow molding body (a) is prevented from being deformedby a resin pressure in the case in which the hollow molding body (a) isset in metal molds 24 and 26 described later and a molten resin is flowninto the metal molds.

The liquid 30 is heated in the metal molds 24 and 26 to a certaindegree. Consequently, it is preferable that such liquid 30 has normalphysical properties even if heated.

In the case in which abnormal physical properties may occur by heating,the liquid 30 that can be heated such as water is flown into the hollowmolding body (a) and removed after a resin filling, and a desired liquidmaterial 22 is then held in the hollow molding body (a).

As a matter of course, a desired liquid material 22 can also be held inthe hollow molding body (a) in advance in such a state. However, thedesired liquid material 22 is heated in the metal molds 24 and 26 to acertain degree as described above. Consequently, only in the case inwhich abnormal physical properties do not occur for the liquid material22, the desired liquid material 22 can be held in the hollow moldingbody (a) in advance.

The liquid 30 to be used in molding is preferably water or alcohol insuch a manner that it is not required to wash the hollow molding body(a) and that the hollow molding body (a) is only dried after thesynthetic resin hollow body (A) is manufactured and the liquid 30 isremoved from the hollow molding body (a).

As shown in FIG. 6( a), the hollow molding body (a) is then set in themetal molds 24 and 26 in such manner that a container portion of thehollow molding body (a) floats in a space in the metal molds 24 and 26.

In this embodiment, a cap member 18 is attached to the opening portion14 of the hollow molding body (a) before the hollow molding body (a) isset in the metal molds 24 and 26. However, a gate (not shown) can beformed in the metal molds 24 and 26 in such a manner that the liquid 30does not flow out of the opening portion 14 of the hollow molding body(a). In addition, a screw shape (not shown) can also be formed on theopening portion 14 of the hollow molding body (a) in advance and theopening portion 14 can be screwed into the metal molds 24 and 26. Bysuch configurations, the hollow molding body (a) can be set in the metalmolds 24 and 26 without attaching the cap member 18 to the hollowmolding body (a).

As shown in FIG. 6( b), the metal molds 24 and 26 are then closed. Asshown in FIG. 6( c), a highly transparent synthetic resin is filled inthe metal molds 24 and 26 via a resin inflow port 28.

By such a process, the highly transparent synthetic resin that has beenmolten is over-molded on the periphery of the hollow molding body (a)from the bottom end of the opening portion 14 of the hollow molding body(a) in the metal molds 24 and 26.

As shown in FIG. 7( a), the metal molds 24 and 26 are opened after thehighly transparent synthetic resin is hardened. As shown in FIG. 7( b),the synthetic resin hollow body (A) is detached from the metal molds 24and 26, and a runner and a sprue are detached. The liquid 30 is thenremoved from the hollow molding body (a). As a result, the syntheticresin hollow body (A) in which a resin sheathing body 16 is formed in anintegrating manner with the hollow molding body (a) can be obtained asshown in FIG. 1. In the case in which the hollow molding body (a) is notprovided with the cap member 18, the liquid 30 is removed from thehollow molding body (a) after the synthetic resin hollow body (A) isdetached from the metal molds 24 and 26, and the cap member 18 isattached to the opening portion 14 of the hollow molding body (a). Bysuch a process, the synthetic resin hollow body (A) in which the resinsheathing body 16 is formed in an integrating manner with the hollowmolding body (a) can be obtained similarly to the above. In this case,the resin sheathing body 16 is welded to an external surface of thehollow molding body (a), thereby preventing the hollow molding body (a)from wobbling or rotating in the resin sheathing body 16. Moreover, theboundary line between the both members is hardly visible, therebyobtaining an improved aesthetic appreciation and an improved appearanceproperty.

In the present invention, a coating, a printing, or a hard coating canbe carried out to the resin sheathing body 16 to impart a flawresistance and a design property to the resin sheathing body 16.

By such a method, after the resin sheathing body 16 is filled with, theliquid 30 is removed from the hollow molding body (a), and a desiredliquid material 22 is flown into the hollow molding body (a).Consequently, the synthetic resin hollow body (A) that holds the liquidmaterial 22 can be manufactured. Therefore, it is unnecessary to adoptthe conventional complicated processes such as defrosting the frozenliquid 30, removing the content, and filling with the liquid material22. Accordingly, a manufacturing cost can be reduced.

Moreover, both the hollow molding body (a) and the resin sheathing body16 are made of a resin. Consequently, the hollow molding body (a) andthe resin sheathing body 16 are not required to be separated from eachother in a disposal, thereby having a satisfactory recycle property.

Furthermore, after the synthetic resin hollow body (A) is manufactured,in the case in which the liquid 30 that has been held in the hollowmolding body (a) in molding is removed and a desired liquid material 22is newly held in the hollow molding body (a), water can be used as theliquid 30 that is held in the holloW molding body (a) in molding.Consequently, the inside wall of the hollow molding body (a) is onlydried after removing water, thereby preventing the manufacturing processfrom being complicated and reducing a manufacturing cost of thesynthetic resin hollow body (A).

Furthermore, the core hollow molding body (a) is made of a resin, andthe resin sheathing body 16 is made of a highly transparent syntheticresin. Consequently, a high quality sense, an aesthetic appreciation,and an appearance property can be extremely improved for the syntheticresin hollow body (A).

FIG. 8 illustrates another embodiment of a synthetic resin hollow body(A) in accordance with the present invention similarly to FIGS. 1 to 7.

The synthetic resin hollow body (A) shown in FIG. 8 has a configurationbasically equivalent to that of the synthetic resin hollow body (A) ofthe embodiment shown in FIGS. 1 to 7. Consequently, elements equivalentto those illustrated in FIGS. 1 to 7 are numerically numbered similarlyand the detailed descriptions of the equivalent elements are omitted.

A point different from the above embodiment for the manufacturing methodof the synthetic resin hollow body (A) shown in FIG. 8 is that a gas 32is used as a fluid substance.

In this case, as shown in FIG. 8( a), a hollow molding body (a) in anempty state is set in the metal molds 24 and 26, and the gas 32 is madeto blow in an opening portion 14 of the hollow molding body (a). At thistime, a pressure of the gas 32 that blows in the hollow molding body (a)is preferably in the range of 0.04 to 1.0 MPa. The gas 32 to be used isnot restricted in particular. For instance, air, nitrogen, oxygen, aninert gas, and a carbon dioxide gas can be used. In particular, air ispreferably used.

As shown in FIG. 8( b), the metal molds 24 and 26 are then closed whilethe gas 32 is made to blow in the hollow molding body (a). As shown inFIG. 8( c), a molten resin is flown into the metal molds 24 and 26 via aresin inflow port 28. By such a process, the molten resin covers the.hollow molding body (a).

The molten resin is cooled and hardened by maintaining this state for acertain time. At this time, by reducing a pressure of the gas 32 thathas blown in the hollow molding body (a) to make the pressure less thanthat at the resin filling, a resin sheathing body 16 can be formed insuch a manner that an external surface of the hollow molding body (a) iscovered in an integrating manner with the resin sheathing body 16without a distortion generated between the hollow molding body (a) andthe resin sheathing body 16. At this time, a pressure of the gas 32 ispreferably reduced to the range of 0.02 to 0.5 MPa.

As shown in FIG. 9( a), the metal molds 24 and 26 are then opened. Asshown in FIG. 9( b), a runner and a sprue are detached, and a cap member18 is attached to the opening portion 14. As a result, the syntheticresin hollow body (A) in which the resin sheathing body 16 is formed inan integrating manner with the hollow molding body (a) can be obtained.

In the manufacturing method in accordance with this embodiment, the gas32 is just made to blow in the hollow molding body (a) in theover-molding on the hollow molding body (a). Consequently, a desiredliquid material 22 can be held in the hollow molding body (a)immediately after the molding, thereby further reducing a manufacturingcost as compared with the above manufacturing method.

In the above manufacturing methods of the synthetic resin hollow body(A), the liquid 30 and the gas 32 are individually used as a fluidsubstance to be flown into the hollow molding body (a). However, acombined use of the liquid 30 and the gas 32 is also possible.

In this case, the liquid 30 is flown into the hollow molding body (a) bythe range of 1% to 50%, preferably the range of 5% to 20%. The hollowmolding body (a) is then set to the predetermined position in the metalmolds 24 and 26 in such a manner that the opening portion 14 is locatedon the upper side without the cap member 18 attached to the openingportion 14 of the hollow molding body (a).

While the gas 32 having a pressure in the range of 0.04 to 1.0 MPa ismade to blow (that is, the gas 32 is made to blow at the pressure in therange of 0.04 to 1.0 Mpa) in the hollow molding body (a) via the openingportion 14, a molten resin is flown into the metal molds 24 and 26 andhardened. As a result, the synthetic resin hollow body (A) in which anexternal surface of the hollow molding body (a) is covered by the resinsheathing body 16 in an integrating manner can be obtained.

In the case in which a combined use of the liquid 30 and the gas 32 iscarried out for a fluid substance to be flown into the hollow moldingbody (a) as described above, it is not necessary to modify a blowingpressure of the gas 32 in the flowing of the molten resin and in thehardening of the molten resin. Moreover, a heat resistance and apressure resistance of the hollow molding body (a) in molding can beimproved as compared with the case of using only the gas 32.Furthermore, as compared with the case of using only the liquid 30, anamount of the liquid 30 to be filled in the hollow molding body (a) canbe reduced, thereby facilitating an exhaust of the liquid 30 from thehollow molding body (a) after molding.

While the preferred embodiments of the present invention have beendescribed above, the present invention is not restricted to theembodiments, and various changes and modifications can be thus madewithout departing from the scope of the present invention. For instance,a liquid and a gas are used as a fluid substance in this specification.However, the present invention is not restricted to this case, andpowder or the like can also be used.

1. A manufacturing method of a synthetic resin hollow body (A) in whicha molten resin is injected for an over-molding outside a hollow moldingbody (a) which is made of a resin, is hollow inside and is provided withat least an opening portion to form a resin sheathing body in anintegrating manner with the hollow molding body (a), which methodcomprising the steps of: filling partially the hollow molding body (a)with a liquid as a fluid substance, the rest of the hollow molding body(a) filled with air, or filling wholly the hollow molding body (a) witha liquid as a fluid substance, attaching a cap member to the openingportion, setting the hollow molding body (a) holding the liquid insideto a metal mold, and injecting the molten resin into the metal mold foran over-molding wherein the liquid is one of water, an aqueous solution,a cosmetic solution, a chemical, and an organic solvent, whereby theresin sheathing body is formed to cover the entire of the hollow moldingbody (a) from the bottom end of the opening portion.
 2. Themanufacturing method of a synthetic resin hollow body (A) as defined inclaim 1, wherein the resin sheathing body is welded to an externalsurface of the hollow molding body (a).
 3. The manufacturing method of asynthetic resin hollow body (A) as defined in claim 1, wherein a boilingpoint of the liquid is at least 50° C.
 4. The manufacturing method of asynthetic resin hollow body (A) as defined in claim 1, wherein themolding temperature is in the range of 100° C. to 300° C. and theinjection pressure is in the range of 20 to 150 kg/cm² in the case inwhich the molten resin is injected into the metal mold.
 5. Themanufacturing method of a synthetic resin hollow body (A) as defined inclaim 1, wherein the molten resin to be injected into the metal mold isan ionomer resin.
 6. The manufacturing method of a synthetic resinhollow body (A) as defined in claim 1, wherein the hollow molding body(a) is formed by a blow molding method or a method of welding twodivided molding bodies using a vibration welding method.
 7. Themanufacturing method of a synthetic resin hollow body (A) as defined inclaim 1, wherein the hollow molding body (a) is a thin-walled moldingbody.
 8. The manufacturing method of a synthetic resin hollow body (A)as defined in claim 1, wherein a thickness of the resin sheathing bodyis at least 1 mm.
 9. The manufacturing method of a synthetic resinhollow body (A) as defined in claim 1, wherein the hollow molding body(a) is a hollow molding container.
 10. The manufacturing method of asynthetic resin hollow body (A) as defined in claim 1, which methodfurther comprises the step of removing the liquid from the hollowmolding body (a) after the molten resin is hardened.